http://www.officeformac.com/ms/microsoft.public.mac.office.entourage Subject says it... after updating to the latest version of Entourage any attempt to send a meeting invitation results in &quot;Unexpected data was encountered... Mail could not be sent.&quot; Error code is -17997. <br><br>Screenshot at <a href="http://www.screencast.com/t/AqxVJLHtc">http://www.screencast.com/t/AqxVJLHtc</a> <br><br>If there are specific Exchange hotfixes implicated in this issue I can check server patch levels to troubleshoot. Fri, 31 Oct 2008 18:10:39 GMT Web Crossing(r) Unix-v6.4 built Jan 14 2010 18:50:13 (source:1372 2010-01-14 15:39:31 -0800)/Unix-6.4 (http://webcrossing.com/) http://backend.userland.com/rss